Automatic burst firing gun having revolving chambers

ABSTRACT

An automatic, burst-firing howitzer is provided having a single tube or gun barrel, and two alternatively and sequentially utilized firing chambers which reciprocate with the tube in recoil and counterrecoil. A loading system is provided to load rounds of ammunition sequentially into the next respective firing chamber during recoil, and to extract the previously fired case from the preceding firing chamber during counterrecoil. The loading system includes a floating, double-ended, spring- and gas-loaded, hydraulic piston system for continuously monitoring the recoil velocity of the recoiling mass and for traversing the round at the appropriate velocity and for the appropriate distance to fully chamber the round by the end of the recoil travel. Depending on the recoil travel the gun can fire out of battery, or in battery.

United States Patent 964,419 7/l9l0 Giustoetal Inventors Robert Ernest Chiabrandy;

John Leonard Arnidon; James Dexter Scanlon, all of Burlington, Vt.

Appl. No, 808,155

Filed Mar. 18, 1969 Patented Aug. 10, 1971 Assignee General Electric Company AUTOMATIC BURST FIRING GUN HAVING REVOLVING CHAMBERS 11 Claims, 34 Drawing Figs. v

U.S. Cl 89/157, 89/43 A, 89/47 Int. Cl F41d 7/04 Field of Search 89/33 MC, 42, 43,43.1,47, 155, 156, 157

References Cited UNITED STATES PATENTS ELEVATlO ASSEMBLY Primary Examiner-Benjamin A. Borchelt Assistant Examiner-Stephen C. Bentley Anomeys-Bailin L. Kuch, Harry C. Burgess, lrving M.

Freedman, Oscar B. Waddell and Frank L. Neuhauser ABSTRACT: An automatic, burst-firing howitzer is provided having a single tube or gun barrel, and two alternatively and sequentially utilized firing chambers which reciprocate with the tube in recoil and counterrecoil. A loading system is provided to load rounds of ammunition sequentially into the next respective firing chamber during recoil, and to extract the previously fired case from the preceding firing chamber during counterrecoil. The loading system ,includesa floating, double-ended, springand gas-loaded, hydraulicpiston system for continuously monitoring the recoil velocity of the recoiling mass and for traversing the round at the appropriate velocity and for the appropriate distance to fully chamber the round by the end of the recoil travel. Depending on the recoil travel the gun can fire out of battery, or in battery.

pmimin m n 3,598,016

SHEET 01 HF 11 IVNVENTORS'.

ROBERT E. CHIABRANDY,

JOHN L. AMIDON JAMES D. SCANLON,

THEIR AT ORN Y.

PATENIED AUG 1 0 um SHEEI Q 3 g;

INVENTORS ROBERT E. CHIABRANDY,

JOHN LAMIDON, JAMES 0. SCANLON,

THEIR ATTORNEY- F1659 3 F|G5f It} I r H w u w @T INVENTORSI 1 274 278 ROBERT E. CHIABRANDY, 276 JOHN L. AMIDON,

5L JAMES 0. SCANLON,

Hashi BY THEIR ATTORNEY.

INVENTORSZ ROBERT E. CHIABRANDY,

JOHN L. AMIDON, JAMES D. SCANLON,

/THEIR ATTORNEY.

PATENTEU AUG 1 0 IQ'ZI SHEET 08 [1F INVENTORS- ROBERT E. CHIABRANDY,

JOHN 1.. AMIDON, JAMES D. SCANLON, BY

/ THEIR ATTORNEY,

PATENTED AUS 1 01921 SHEET 07 0F INVENTORS ROBERT E. CHIABRANDY,

JOHN 1.. AMIDON, JAMES oz gLou, THEIR ATTORNEY.

' PATENTED'AUBIOIBYI SHEET 08 OF INVENTORSK ROBERT E. CHIABRANDY,

JOHN L.AMIDON, JAMES o. SCANLON,

BY /THEIR TTO NEY.

PATENTEUAUBIOIWI 3 59 015 SHEET 09 0F 11 INVENTORS ROBERT E. CHIABRANDY,

JOHN L. AMIDON, JAMES D. SCANLON,

/ THEIR ATTORNEY.

PATENTEUAUGIOIQYI 3.598.016

Sam 10 0F 11 5'8 FIG.90 (OELEVATION,F!RING) FlG.9b (OELEVATION,RECOIL) mvnunim v ELEVATION NITROGEN RECOIL STlFFENER BRAKE OIL 0 INVENTORS ROBERT E. CHIABRANDY, JOHN L. AMIDON, JAMES D. SCANLON,

/ THEIR ATTORNEY.

PATENTEU AUBIOIQ'H 3 59 01 SHEET 11 [1F 11 CARTRIDGE HOLD BACK BATTERY LOADED AND I? FROM POSITION TRAY RELEASE BATTERY COUNTERRECOIL BUFFER r IGJO FAST COUNTERRECOlL RAM CLOSURE RAM RETURN READY To A FIRE INDEX DWELL mDEx CHAMBER FEED I CHAMBER ExT AcT AND EJECTION FIG.

E E J\ BATTERY BATTY POSITION POSITN sTART CYCLE k LANYARD PULL A HEAVILY DAMPED COUNTERRECOIL RECO'L BRAKE COUNTERRECOIL BUFFER SLOW FAST RECO'L COUNTERRECOIL COUNTERRECOIL RAM CLOSURE RAM RETURN Q FIRE ouT Q FIREIN 0F BATTERY BATTY INDEX DWELL INDEX 50 80 50 cRAmBER I FEED CHAMBER ExT AcT EXTRAJCT AND EJECTION FIG. l2

A sTART CYCLE SYSTEM HALTS LANYARD PULL l7"OUT OF BATTERY RECOIL BRAKE HEAVILY DAMPED BUFFER 'NVENTORS' COUNTERRECOIL SPRING ROBERT E. CHIABRANDY. SLOW JOHN L.AM|DON, COUNTERRECOIL J ME A cANL RAM LOCKED To REAR BY THEIR ATTORNEY.

AUTOMATIC BURST rrnmc can nnvnvc npvo 'v CHAMBERS BAcxoRouNo or THE invention 1. Field of the,

Invention This invention relates to rapid firing artillery, and especiallyto a heavy artillery piece adapted o fire a rapid burst of rounds; e.g., a burst-firing howitzer,

2. Prior Art The conventional heavy artillery piece includes abarrel assembly and a breech mechanism mounted ona. recoil support mechanism. The distance of the recoil travel is mainly a func-. tion of the recoil impulse generated by the charge of powder explodcd, to fire the projectile from the gun. It is also, inter alia, a function of the angle of elevation of the barrel as: c ycnven i n lcuns'designed for rela ively rapid fire usually fire fixed ammunition, Le the projectile-is fixed to its powder canister. Thus, fora given type of ammunitionth'e charg f p der fir will be sub ant al y uniform- Th minor variation Which might be caused by changes in the angle of elevation can be compensated for by changing the stiffness of the recoil buffer system. Therefore, in fixed ammunition firing guns, the distance of recoil travel is substantially invariable, o.e., subject to a variation of less than 10 percent. Historically, a round of ammunition wasloaded into the breech after BRIEF DESCRIPTION or THE DRAWING These and-other objects, features and advantages of the invention will be apparent from the following specification thereof taken in conjunction with the accompanying drawing in which:

FIG. 1 is a perspective view of a rapid fire howitzer embodying this invention;

' FIG. 2 is a simplified perspective view of the recoiling parts of the howitzer of FIG. 1;

FIG. 3a is a rightside elevation of the recoiling parts, FIG. 3b is a rear elevation, and FIG. 3c is a front elevation detent;

FIG. 4a is a right side elevation of the tipping parts, and FIG. 4b is a front elevation;

FIG. 5a is aright side elevation of the ram and tray assembly, FIG. 5b is a rear elevation, FIG. 50 is a top plan, FIG. 5d is arear elevation detail, showing the ram holdback device FIG. Se is arightside elevation detail of the forward motion lock, FIG. 5f is a side elevation detail and FIG. 5g is a rear elevation detail ofa forward'motion lock, FIG. Si is a right side elevation detail of the cartridge support, and FIG. 5h is a rear elevation detail; FIG. 6 is a left side elevation schematic diagram of the ram 7 power mechanism;

the breech mechanism had completed its counterrecoil travel and was in battery,'i.c., in its forwardmost, firing position. This required a firing cycle wherein-the. time spent in recoil and counterrecoil was wasted as faras loading was concerned. in an effort to shorten the firing; cycle, some automatically loadedguns have provided for-ran initiation of the loading I operation while the gun is traveling in counterrecoil. However, these guns have requircdahinvariable distance of recoil travel. Such a system works. quite well for relatively lightweight weapons, such as the 75 mm. AA gun and lighter weapons, which firefixed ammunition.

However, in a 105mm. howitzer firing semifixed ammunition, a variation of recoil impulse of 5:1 maybeencountcred; If this were not buffered, a variation. of recoil travel of 25:1 would result, but by the use of preloaded spring-hydraulic buffers, this can be reduced to 4:1 variation of recoil travel, e.g.,

72 to 17 inches. A skilled gun crew can start loading at about the time the weapon commences counterrecoil, and cancomplete loading by the time it reaches batteryllowever, conventional loading devices cannot. 1

A related problem is that thefuzes and rotating bands on many projectiles are quite sensitive to accelerations [t is desirable to chamber the roundat as low a relative velocity between the round and the breech as possible.

A burst-firing gun has been disclosed in -U.S Pat. No.- 3,535,980, issued Oct. 27, l970 to Robert E. Chiabrandy and George H. Bloom, which is well Suited to this application. 'In that gun, the ammunition-loading system continually monitors the recoil velocity of the breech and continually traverses the round to be chambered inthe appropriate direction and at an SUMMARY OF- THE INVENTION lt is an object of this invention to provide a heavy weapon system having an ammunition-loadi g subsy tem for automati cally, repeatedly, rapidly loading the weapon with semifixcd ammunition; which ammunition may be acceleration-sensitive with respect to its fuze and rotating band.

A feature of this invention is t e provision of a heavy weapon having an ammunition-loading subsystem which continually monitors the recoil velocity of the breech and continuully traverses the round forward at an appropriate velocity with respect to the recoiling breech so that the round will be chambered as the breech reaches the end of its recoil travel, wherever that may occur. The round may be fired out of battery.

FIG. 7a is a top plan of the recoil system, and FIG. 7b is a rearelevation;

FIGS. 8a through 8/: are left side perspective details of the operation sequence.

. FIG. 9a is a hydraulic schematic of the recoil system at 0 elevation in the firing disposition, FIG. 9b is in the recoil disposition, FIG. 90 is at 75 elevation, and FIG. 9d is in the rccoil'disposition.

FIG. 10 is a chart ofthe loading sequence for chambering; FIG. H i a chart of the automatic firing cycle; and FIG. 12 isv a chart of the rnanual or last-shot cycle.

DESCRIPTION OF THE PREFERRED EMBODIMENT placement ramming stroke. The two-chambered breech which is fixed fore and aft to a breech support, recoils with the tube axially forward of the lower chamber. These parts recoil and counterrecoil on the cradle ways. A rammer and tray assembly is not rigidly attached to the recoiling parts, but is coupled thereto by a floating piston assembly.

-- The sleigh 20 is a monoblock forging comprising a forward tube support 22 and an aft breech 24 connected by right and left tie rods 26, 28.. A plurality of forward right and left, upper and lower sleigh rollers 30 are journaled in the tube support, and a plurality of rear right and left, upper and lower sleigh rollers 32 are journaled in the breech. A chamber block 46 comprises twospaced-apart chamber tubes 48, 50 integrally connected by a web 52 The web 52 has a longitudinal bore,

' and fore and aft extending collars 56,58 which are mounted in two pillow blocks 60, 62 respectively mounted on the tube support and the breech. Four chambersv shear flanges 64 extend aft, from the chamber block and interlock two at a time,

' with two breech grooves, to maintain the desired head space.

A ringshaped, chamber-indexing gear 68 is fixed to the periphery of the chamber block 46. A tubular index cam 70 is mounted, for rotation to the tube support 22 by ring plate 72 bolted to the support and by a forward journal 74 supported by two cantilever beams 76 also mounted to the ring plate. The index cam 70 has two internal cum tracks 78 and an external ring gear 80. The ring gear is coupled to the chamber indexing gear 68 by an idler set of gears 82, 84 journaled through the tube support. The aft end of the tube 86 has a plurality of interrupted buttress threads 88 and passes through the chamber indexing cam into the tube support. A tapered lock pin 90 passes radially through the tube into the support for alignment.

A breech block 92 is releasably mounted by interrupted threads on the breech ring 94 and carries the firing lock 96'.

Mounted beneath, to and between the tube support and the breech are the recoil brake housing 98 and the recuperator assembly 100. Captured between the tube support and the breech is a magazine indexing cam 102 which rides on a magazine drive shaft 104 which is attached to a cradle 106. A magazine cam follower block 108 rides in a track 110 in the magazine indexing cam 102 and in a track 111 in a cam follower support 112 attached to the right tie rod 26. Mounted on the cradle is a spring-loaded sliding rod 113, and a set of pivoting links 114 which couple the rod to a friction clutch plate 115. An articulated lug 116 is pivotally mounted to the cradle and is swung out laterally by the rod. A buffer spring 117 is mounted on the tube support and is adapted to be compressed by pivotal movement of an impact lever 118.

The recoiling parts recoil in the cradle. The cradle 106 comprises right and left longitudinally extending cradle ways 128, 130 of channel construction which receive the sleigh rollers. The ways are transversely connected into a rigid structure by a lower shear structure 132, fore-and-aft hoops 134, 136, intermediate lower C-shaped frames 138, and fore-and-aft box beams 140, 142. Fore-and-aft pillow blocks 144 mounted to the fore-and-aft hoops support, for rotation only, the magazine drive shaft 104. A cradle gear rack 148 extends longitudinally and is fixed to the shear structure 132. The piston 150 of the recoil brake extends longitudinally and is anchored to the fore box beam 140. Longitudinally extending right and left tray ways 143, 145 of channel construction are respectively fixed to and above the right and left cradle ways by spacer elements 146. A magazine assembly 150 is hinged at four points to a boss structure 152 fixed to the right cradle way 128.

The cradle is supported on the top carriage assembly 164. The top carriage assembly comprises a base plate 166, right and left support arms 168, 170 extending upwardly-rearwardly from the base plate, and an azimuth bearing, not seen. Right and left equilibrators 174, 176 are respectively coupled to and between the right and left support arms and the right and left cradle ways. Right and left trunnion lugs are bolted respectively to the right and left cradle ways and are journaled respectively in bearings on the right and left support arms. Passing through the equilibrators are right and left elevating ball screws. A gear train is driven by a hand wheel 178, and drives the elevating ball screws.

The recoil system comprises the recoil brake housing 98 fixed to the recoiling parts, the recoil piston 150 fixed to the cradle, and the recuperator cylinder 100 fixed to the recoiling parts. Disposed in the recuperator cylinder 100 are a floating elevation piston 180, operating in the aft end of a nitrogen reservoir 182 which is divided by a plate 184 having an orifice 186, and a floating recuperator piston 188 having a throttling rod and groove. An oil bypass port 190 couples oil between the recoil cylinder and the forward end of the recuperator cylinder which is filled with oil. A telescoping tubular conduit 192 is anchored to and through the cradle forward box beam 140, passing through the recoil cylinder 98, and is coupled to the aft end of the recuperator cylinder 100 to supply oil to the aft face ofthe floating elevation piston 180.

The magazine assembly 150 includes a housing 200, of C- shaped cross section hinged to the right cradle way, having foreand-aft end plates 202, 204, journaling a central longitudinal axle 206 which supports three sprockets 208. The fore plate has a loading door 210 laterally cantilevered therefrom. The door is actuated by a magazine lever 212 which swings the door counterclockwise over a loading tray to receive a round, and which subsequently swings clockwise to transfer the round into the sprockets and to index the sprockets for the next round. A ratchet indexing linkage mechanism 214 is mounted on the aft end plate 204 and is coupled to the magazine drive shaft 104 for oscillation thereby.

The tray assembly comprises a tray cradle 250 having arms extending laterally with a plurality of right and left upper and lower rollers 252 riding within the right and left tray ways. A socket-type journal 254 is formed on the upper surface of the cradle to receive a knuckle 256 formed on the lower end of a web 258 whose upper end is integral .with the tray 260. A tray indexing lever assembly 262 includes a crank arm 264 keyed to the magazine drive shaft, a coupling link 266 coupled I between the arm and the tray, and a support base 268 fixed to the cradle and riding on the shaft. Four pivoting supports 270 are mounted on the tray to support the projectile off the tray to clear the cartridge extractor rim and the rotating bands. Two pivoting retainers 272 are mounted on the tray, to hold the cartridge and the projectile down on the supports 270. A forward motion lock assembly 274 is provided to prevent forward motion of the round prior to chambering and includes a pivoted lug 276 which is spring loaded against the rotating band of the round until released by rearward movement of a release plunger 278 caused by abutment cartridges, the breech ring. An extractor assembly 280 is carried by the tray for the extraction of the fixed cartridges, as shown in FIGS. 5b and 8a through 8h, and has three arms with dependent fingers adapted to receive and grasp the extractor rim ofthe fired cartridge case, as shown in FIGS. 8d, 8e and 8f.

The ram assembly comprises a ram 300 which rides through a slot 302 in the tray and has an articulated connection 304 with the aft end of a ram rod 306 having a gear rack 308 formed thereon. A cam drive roller 310 is mounted on the forward end of the ram rod and mates with the chamber index cam track 78. A replenisher, ram damper and return cylinder 312 is pivotally mounted at its front end to the forward yoke 313 of the recuperator 100. A ram'actuator cylinder 314 is journaled in a bore 316 in the tube support 22. A gear rack 318 is formed on the cylinder 314. A ram actuator rod 320 has a forward piston 322 disposed in the cylinder 312, an aft piston 324 in the cylinder 314, and a gear rack 326. Nitrogen at l040 p.s.i. preload is disposed in the cylinder 314. A check valve 327 having free flow aft and a constricted orifice 332, a floating piston 333, and a compression spring 336 are disposed in the cylinder 312. Hydraulic oil is disposed between the piston 322 and the piston 333. A gear train comprising a first gear 328 meshed with the cylinder gear rack 318, and a second gear 330 meshed with the first gear and the cradle gear rack 148 are journaled to a cantilevered arm 832 extending from the left tie rod 28. A unidirectional clutch 834 is adapted to disengage the gear train 328, 330 during index ing of the chamber block 46. The chamber index follower block also operates a linkage 836 to reciprocate a pin 338 to assure alignment of the chamber block. A ram holdback assembly, comprising a toggle linkage 340 and a round sensing lever 342, is adapted to engage detents 343 in the light and left cradle ways.

OPERATION ln burst firing, the first operation to be performed is loading the five-cartridge magazine. The assistant gunner unlocks the magazine-indexing lever 212, rotates the handle lc and then pushes the handle forward 30 to open the magazine loading door 210. The No. l crewman places a cartridge on the loading door and slides it aft until it abuts the aft end plate 204. The assistant gunner then rotates the magazine indexing lever back l l l", which loads the cartridge into the sprockets 208 and indexes the sprockets one position which is 72. This operation is repeated four times to fully load the magazine. Any number of cartridges up to five may be loaded in the magazine. A sixth cartridge is fed into the sprockets and when the sprockets are indexed, the linkage 214, which is coupled between the sprocket shaft 206 and the magazine drive shaft 104, oscillates the shaft 104 and the tray 260 which is keyed thereto, to receive the first cartridge from the sprockets. The cartridge depresses the sensing lever 342 to enable the tray, when it swings back up, to unlock the ram holdback linkage 340.

Assuming the ram power mechanism to be uncharged, it is necessary to manually load a first cartridge 580 into the chamber. This is accomplished by manually operating a linkage, not shown, which withdraws the alignment pin 336 and,

pulling a lanyard to operate an in-battery sear 400 on the right cradle way, to operate a trigger shaft, which operates the firing lock 96, to fire the chambered cartridge. The tube and the breech recoil along the cradle, and via the gear train 328/330 journaled to the tube support, move the ram actuator cylinder 314 .forward with respect to the anchored cradle rack 148. The cylinder 314 biases the aft piston 324 forward, which via the ram rack 326,the gear train 340/342, and the ram rod rack 83 drives the ram rod 306 and the ram 300 forward. The velocity of the ram is limited by the forward piston 322 biasing oil through'the orifice 332 of the check valve 327 against the floating piston 333 and the spring 336. The ram is locked to the tray cradle by a roller detect 402 retained by a springloaded piston 404, and carries the tray, with a cartridge thereon, forward, as shown in FIGS. and 80. When the forward end of the plunger 278 abuts the breech, the forward motion lock 276 is swung out of the way of the cartridge.

When the forward end of the spring-loaded piston of the tray lock abuts the breech, the roller detent 402 of the tray cradle is transferred to the breech, as shown in FIG. 8b. The ram continues to travel forward, with respect to the now stationary tray, bringing forward the extractor 280, to the front of the tray cradle, and transferring a ball lock 410 from an interlock between the extractor and the ram to an interlock between the extractor and tray cradle, as shown in FIGS. 5a and 8c. The ram continues forward, through the slot 302 in the tray, and when it reaches 135 inches from full closing, its shoulder engages the chamber cam follower block 310, moving it l.5 inches, which block, through a linkage, disengages the alignment block 336 from this chamber. The next 12 inches of ram rod closure drives the chamber cam follower block within the cam slot 78, and indexes the chambers via the cam 70 and gear train 80, 82, 84 and 68. The ram, tray and extractor index with the chambers 50 and continue 28 additional, coming to rest 78 from the vertical, as shown-in FIG. 8d. After 80 of chamber dwell, a cam surface 416 operates the clutch 834 to disengage the cylinder gear rack 318 from the cradle rack 148 alignment block. When the ram has extended to its original position with respect to the extractor, the lock between the extractor and the tray support is transferred back, securing the extractor to the ram rod. The ram extractor and the cartridge cam continue to travel to; the rear, extracting the cartridge case from the chamber, as shown in FIG. 8a. When the ram rod has reached full extension with respect to the tray cradle, the tray cradle is unlocked from the breech and locked to the ram rod. The entire ram and tray assembly with the extracted cartridge case travels to the feeding position at the rear of the cradle, as shown in FIG. 8f; The ram holdback device 340 secures the ram and tray mechanism in the fired position.

The recoil travel of an tube and breech is variable, depending on the charge and elevation. The kinetic energy of these recoiling parts is transferred to the recuperator, from which energy is taken to'perform the magazine indexing and feeding function during burst firing, and to preload the nitrogen in the ram actuator cylinder for subsequent forward movement of the ram and tray in the loading operation. To accomplish this, the recoiling parts are permitted to traverse their full recoil, whatever this distance may be for the particular charge and elevation, and to commence counterrecoil. However, completion of counterrecoil is not permitted (1) until after the ram and tray have reached their feed position in automatic firing, and (2) on firing the last round.

To achieve the required out-of-battery holdback, the lug 116 normally is forward of and swung out laterally in the path of the impact lever 118, and will halt the recoil of the tube support and the associated recoiling parts 17 inches out of battery. As the ram and tray travel the last 2 inches of movement intothe load position, the tray cradle engages and moves the rod113 to the rear, swinging the lug 116 out of the way of the impact lever 118. The recoiling parts are then free to continue forward into battery, until the impact l'ever 118 abuts the for ward end of the right cradle way. The rearward movement of the rod 113 also engages the friction plate with the cam follower block 108 to anchor the cam follower block 108 to the cradle. The now-anchored cam follower block rides in both the track 111 in the support 112 on the right tie rod 26 and the track 110 on the magazine indexing cam, and as these tracks moveforward, causes indexing of the track 110 with respect to the track 111, thereby indexing the magazine, and transferring a cartridge case from the sprockets to the tray, as shown in FIG. 8g. The cartridge case on tray,-tray as the tray swings up to vertical, unlocks the ram holdback linkage 340 from the cradle. The springs 336 continue to bias the ram rearward. During the indexing of the tray to the vertical position, the extracted cartridge case is tip and ejected rearwardly, as shown in FIG. 8h. The sleigh and tube assembly continue forward into battery and are buffered to a stop by the spring 117. On a long recoil, the tray cradle will normally reach its loading position,- operate the rod 113 to lock the magazine cam follower block to the cradle and effect indexing of the magazine early enough for the magazine cam follower block, after 4 inches of. additional travel, to act as an out of battery sear and impact the trigger shaft of the firing lock. If the indexing operation commenced from the out of battery holdback position, then the in-battery sear 400 will impact the trigger shaft of the firing lock when the sleigh and the tube reach battery. And the next cartridge is fired.

, When the last cartridge is in the firing chamber in line with the firing tube, and no cartridge is left in the magazine or on the tray, and the last cartridge is fired, the recoiling parts recoil and charge the ram power mechanism. The ram and tray cannot move forward, since no cartridge is now on the tray to unlock the ram holdback device. Counterrecoil returns the recoiling parts to the out-of-battery, charged position.

To speed the rate of fire and to prevent tipping when the recoiling parts are halted out of battery, the counterrecoil is heavily damped by the recoil system during the interval between the start of counterrecoil and the tray cradle reaching loading position. The oil bypass 190 between the recuperator cylinder 100 and the recoil cylinder 98 during counterrecoil is constricted by an overcenter spring-loaded, apertured shutter 500. When the rod 113 is shifted by the cradle tray reaching its loading position, a linkage not shown, withdraws the shutter to allow free flow of oil. The shutter remains withdrawn during recoil, until the reversal of oil flow at the start of counterrecoil tripsthe overcenter spring to shift the shutter closed.

The elevation stiffener serves to provide a variable load on the recoiling parts, responsive to elevation, via the recuperator. The outlet 510 of an elevation cylinder 511 is coupled by a conduit 512 through the cradle front box beam through the telescoping conduit 192-disposed in the recoil cylinder 98 through a conduit 516, into the aft end of the recuperator cylinder 100. Operation of the elevation handwheel moves a piston 518 in the elevation cylinder 511 to control the flow of oil through the conduits against the elevation free piston 180, providing a variable compression of the nitrogen in the recuperators.

What We claim is:

1. An automatic, rapid firing, artillery piece, piece adapted to fire rounds of variable energy providing variable recoil travel, comprising:

support means having a first longitudinal axis;

a single tube, having a second longitudinal axis parallel to said first longitudinal axis, and mounted to said support means for reciprocation along said second longitudinal axis in recoil and counterrecoil;

a breech assembly, having a plurality of chambers disposed in an annular row about a third longitudinal axis which is parallel to said first longitudinal axis, and mounted to said support means aft of said tube for reciprocation along said third longitudinal axis in recoil and counterrecoil and for rotation about said third longitudinal axis whereby to sequentially align each of said plurality of chambers with the aft end of said tube on said first longitudinal axis; and

loading means, mounted to said support means, including transport means for transporting a round of ammunition forwardly along a path parallel to said third longitudinal axis from an aft, fixed supply station, sensing means coupled to said breech assembly for providing a signal responsive to the recoil velocity of said breech assembly, and first actuating means coupled to said transport means and said sensing means for moving said transport means forward at an appropriate variable velocity to a variable station at a variable distance forward along said path which will be functionally adjacent the aft end of one of said chambers at the nadir of recoil travel of said breech assembly, whereby the round will be chambered in said one chamber at relatively low velocity between said transport means and said breech assembly.

2. An artillery piece according to claim 1 wherein:

said breech assembly includes:

a breech containing said plurality of chambers; and

second actuating means for indexing said breech about said third longitudinal axis to shift the next chamber in sequence into alignment with said tube.

3. An artillery piece according to claim 1 wherein:

said breech assembly includes:

a breech containing said plurality of chambers which are two in number and disposed diametrically about said third longitudinal axis;

second actuating means for rotating said breech for shifting the last-fired chamber out of alignment with said tube and the loaded chamber into alignment with said tube; and

extraction means, operable during the counterrecoil travel of said breech, for extracting the case of the last-fired round from the last-fired chamber.

4. An artillery piece according to claim 1 wherein:

said sensing means includes:

a first rack which is stationary with respect to said support means,

a second rack which is reciprocable with respect to said support means, and

a first gear train which is journaled to said tube for reciprocation therewith along said second longitudinal axis and is meshed with said first and second racks;

said transport means includes:

a third rack which is reciprocable with respect to said support means; and

said first actuating means includes:

a fourth rack which is resiliently coupled to said second rack and is reciprocable with respect to said support means, and a second gear train which is journaled to said tube for reciprocating therewith along said second iongitudinal axis and is meshed with said third and fourth racks.

5. An artillery piece according to claim 4 wherein:

said second rack is fixed to a first cylinder which is reciprocable along said second longitudinal axis, and

said fourth rack is fixed to a first piston disposed in said first cylinder and is fixed to a second piston disposed in a second cylinder which is secured to said tube for reciprocation therewith along said second longitudinal axis.

6. An artillery piece according to claim 5 wherein: said first piston 18 biased forwardly along said second longitudinal axis by a compressed gas in said first cylinder, and

said second piston is biased rearwardly along said second longitudinal axis by a compressed spring,

7. An artillery piece according to claim 6 wherein:

said second piston on moving forwardly compresses oil through a unidirectional constriction having free flow on rearward movement.

8. An artillery piece according to claim 4 wherein:

said breech assembly includes:

a breech containing said plurality of chambers which are two in number and disposed diametrally about said third longitudinal axis;

a cam coupled to said breech for rotation therewith,

a cam follower-driver interengaged with said cam,

said third rack being coupled to said cam follower-driver to reciprocate said cam follower-driver to index said cam whereby to index said breech for shifting the last fired chamber out of alignment with said tube and the loaded chamber into alignment with said tube.

9. An artillery piece according to claim 8 wherein said transport means further includes:

extraction means, coupled to said third rack, for extracting the case of the last fired round from the last fired chamber, and

tray and ram means, coupled to said third rack for chambering a new round in the next-to-be-fired chamber,

the new round being chambered during recoil, said breech being indexed at the end of recoil and the beginning of counterrecoil and the last-fired round being extracted during counterrecoil.

10. An artillery piece according to claim 6, wherein:

said first gear train includes a unidirectional clutch adapted to disengage during counterrecoil.

11. An artillery piece according to claim 5 further includa recoil brake housing fixed to said breech assembly for reciprocation therewith;

a recoil piston fixed to said support means and disposed in said recoil brake housing;

a recuperutor cylinder fixed to said breach assembly for reciprocation therewith, and coupled to said recoil brake housing by a unidirectional constriction;

an aft floating elevation piston disposed in said recuperator cylinder between a reservoir of elevation stiffener oil and a reservoir of recoil damping gas;

a forward floating recuperator piston disposed in said recuperator cylinder between said reservoir of recoil damping gas and a reservoir of recoil brake oil which is disposed in part in said brake housing and in part in said recuperator cylinder; and

means for varying the pressure on the reservoir of elevation stiffener oil in response to the elevation of said tube. 

1. An automatic, rapid firing, artillery piece adapted to fire rounds of variable energy providing variable recoil travel, comprising: support means having a first longitudinal axis; a single tube, having a second longitudinal axis parallel to said first longitudinal axis, and mounted to said support means for reciprocation along said second longitudinal axis in recoil and counterrecoil; a breech assembly, having a plurality of chambers disposed in an annular row about a third longitudinal axis which is parallel to said first longitudinal axis, and mounted to said support means aft of said tube for reciprocation along said third longitudinal axis in recoil and counterrecoil and for rotation about said third longitudinal axis whereby to sequentially align each of said plurality of chambers with the aft end of said tube on said first longitudinal axis; and loading means, mounted to said support means, including transport means for transporting a round of ammunition forwardly along a path parallel to said third longitudinal axis from an aft, fixed supply station, sensing means coupled to said breech assembly for providing a signal responsive to the recoil velocity of said breech assembly, and first actuating means coupled to said transport means and said sensing means for moving said transport means forward at an appropriate variable velocity to a variable station at a variable distance forward along said path which will be functionally adjacent the aft end of one of said chambers at the nadir of recoil travel of said breech assembly, whereby the round will be chambered in said one chamber at relatively low velocity between said transport means and said breech assembly.
 2. An artillery piece according to claim 1 wherein: said breech assembly includes: a breech containing said plurality of chambers; and second actuating means for indexing said breech about said third longitudinal axis to shift the next chamber in sequence into alignment with said tube.
 3. An artillery piece according to claim 1 wherein: said breech assembly includes: a breech containing said plurality of chambers which are two in number and disposed diametrically about said third longitudinal axis; second actuating means for rotating said breech for shifting the last-fired chamber out of alignment with said tube and the loaded chamber into alignment with said tube; and extraction means, operable during the counterrecoil travel of said breech, for extracting the case of the last-fired round from the last-fired chamber.
 4. An artillery piece according to claim 1 wherein: said sensing means includes: a first rack which is stationary with respect to said support means, a second rack which is reciprocable with respect to said support means, and a first gear train which is journaled to said tube for reciprocation therewith along said second longitudinal axis and is meshed with said first and second racks; said transport means includes: a third rack which is reciprocable with respect to said support means; and said first actuating means includes: a fourth rack which is resiliently coupled to said second rack and is reciprocable with respect to said support means, and a second gear train which is journaled to said tube for reciprocating therewith along said second longitudinal axis and is meshed with said third and fourth racks.
 5. An artillery piece according to claim 4 wherein: said second rack is fixed to a first cylinder which is reciprocable along said second longitudinal axis, and said fourth rack is fixed to a first piston disposed in said first cylinder and is fixed to a second piston disposed in a second cylinder which is secured to said tube for reciprocation therewith along said second longitudinal axis.
 6. An artillery piece according to claim 5 wherein: said first piston is biased forwardly along said second longitudinal axis by a compressed gas in said first cylinder, and said second piston is biased rearwardly along said second longitudinal axis by a compressed spring.
 7. An artillery piece according to claim 6 wherein: said second piston on moving forwardly compresses oil through a unidirectional constriction having free flow on rearward movement.
 8. An artillery piece according to claim 4 wherein: said breech assembly includes: a breech containing said plurality of chambers which are two in number and disposed diametrally about said third longitudinal axis; a cam coupled to said breech for rotation therewith, a cam follower-driver interengaged with said cam, said third rack being coupled to said cam follower-driver to reciprocate said cam follower-driver to index said cam whereby to index said breech for shifting the last fired chamber out of alignment with said tube and the loaded chamber into alignment with said tUbe.
 9. An artillery piece according to claim 8 wherein said transport means further includes: extraction means, coupled to said third rack, for extracting the case of the last fired round from the last fired chamber, and tray and ram means, coupled to said third rack for chambering a new round in the next-to-be-fired chamber, the new round being chambered during recoil, said breech being indexed at the end of recoil and the beginning of counterrecoil and the last-fired round being extracted during counterrecoil.
 10. An artillery piece according to claim 6, wherein: said first gear train includes a unidirectional clutch adapted to disengage during counterrecoil.
 11. An artillery piece according to claim 5 further including: a recoil brake housing fixed to said breech assembly for reciprocation therewith; a recoil piston fixed to said support means and disposed in said recoil brake housing; a recuperator cylinder fixed to said breach assembly for reciprocation therewith, and coupled to said recoil brake housing by a unidirectional constriction; an aft floating elevation piston disposed in said recuperator cylinder between a reservoir of elevation stiffener oil and a reservoir of recoil damping gas; a forward floating recuperator piston disposed in said recuperator cylinder between said reservoir of recoil damping gas and a reservoir of recoil brake oil which is disposed in part in said brake housing and in part in said recuperator cylinder; and means for varying the pressure on the reservoir of elevation stiffener oil in response to the elevation of said tube. 